Day: March 29, 2018

Today, Apple is known for iPhones, iPads, and a commitment to graphical user interfaces. But that wasn’t how it all started. The original Apple was a single board computer built around a 6502. In 1976, you could snag one for $666.66, but you needed to supply your own TV, power supply, and keyboard. [Alangarf] didn’t have an Apple 1, but he did have a 6502 CPU core for FPGAs from [Andrew Holme] that he fleshed out to an Apple I clone with a VGA output and PS/2 keyboard port. The project works with either an iCE40 board or a Terasic DE0 board. You could probably port it to other similar FPGAs.

This is much more practical than trying to find an original, as Apple bought a lot of the old boards back and destroyed them. According to the Apple-1 Registry there are only about 71 of the boards still in existence, and that’s with the annotation that 4 of those may be lost and 8 might be duplicates. We’ve heard that of those there are only six that actually still work.

Cutting every corner can lead to some shoddy projects, but [Terry Gilliam] shows us that cutting the right corners yields unforgettable animations when mixed with the right amount of quirky imagination. The signature animation style of Monty Python’s Flying Circus is a mixture of [Terry]’s artistic craft and doing it with as little work as possible. You can watch after the break.

For [Terry], cutout animation is the quickest and easiest way he knows to convey an idea, a joke, or a story. With his vocal repertoire, even the sound effects can be produced in a basement studio. Sometimes, he makes the artwork himself and sometimes he relies on found-media in magazines or print. Both of these resources have vast digital counterparts for the betterment or detriment of animators.

Cutout animations have limitations such as jerky movement and the signature paper-on-a-background look, but that didn’t stop South Park. Textures and gradients can be used, unlike traditional animation which leverages a simplified color palette so you can pick your poison.

If your story or idea is held back because it can’t be expressed, maybe it needs a cutout animation kick in the right direction, and it couldn’t hurt to illustrate your 2018 Hackaday Prize submissions. At the opposite end of the tech spectrum, we have an animation made with 3D printed objects.

If anything about electronics approaches the level of black magic, it’s antenna theory. Entire books dedicated to the subject often merely scratch the surface, and unless you’re a pro with all the expensive test gear needed to visualize what’s happening, the chances are pretty good that your antenna game is more practical than theoretical. Not that there’s anything wrong with that — hams and other RF enthusiasts have been getting by with antennas that work without really understanding why for generations.

But we’re living in the future, and the tools to properly analyze antenna designs are actually now within the means of almost everyone. [Andreas Spiess] recently reviewed one such instrument, the N1201SA vector impedance analyzer, available from the usual overseas sources for less than $150. [Andreas]’s review does not seem to be sponsored, so it seems like we’re getting his unvarnished opinion; spoiler alert, he loves it. And with good reason; while not a full vector network analyzer (VNA) that will blow a multi-thousand dollar hole in your wallet, this instrument looks like an incredible addition to your test suite. The tested unit works from 137 MHz to 2.4 GHz, so it covers the VHF and UHF ham bands as well as LoRa, WiFi, cell, ISM, and more. But of course, [Andreas] doesn’t just review the unit, he also gives us a healthy dose of theory in his approachable style.

HairIO is based on the idea that hair is an important part of self-expression, and that it can be a natural platform for sandboxing wearable interactivity. Each hair extension is braided up with nitinol wire, which holds one shape at room temperature and changes to a different shape when heated. The idea is that you could walk around with a straight braid that curls up when you get a text, or lifts up to guide the way when a friend sends directions. You could even use the braid to wrap up your hair in a bun for work, and then literally let it down at 5:00 by sending a signal to straighten out the braid. There’s a slick video after the break that demonstrates the possibilities.

HairIO is controlled with an Arduino Nano and a custom PCB that combines the Nano, a Bluetooth module, and BJTs that drive the braid. Each braid circuit also has a thermistor to keep the heat under control. The team also adapted the swept-frequency capacitive sensing of Disney’s Touché project to make HairIO extensions respond to complex touches. Our favorite part has to be that they chalked some of the artificial tresses with thermochromic pigment powder so they change color with heat. Makes us wish we still had our Hypercolor t-shirt.

One of the most interesting developments in 3D printing in recent memory is the infinite build volume printer. Instead of a static bed, this type of printer uses a conveyor belt and a hotend set at an angle to produce parts that can be infinitely long in one axis, provided you have the plastic and electricity. For this year’s Hackaday Prize, [inven2main] is exploring the infinite build volume design, but putting a new spin on it. This is a printer with a conveyor belt and a SCARA arm. The goal of this project is to build a printer with a small footprint, huge build volume, no expensive rails or frames, and a low part count. It is the most capable 3D printer you can imagine using a minimal amount of parts.

Most of the documentation for this build is hanging around on the RepRap forums, but the bulk of the work is already done. The first half of this build — the SCARA arm — is well-traveled territory for the RepRap community, and where there’s some fancy math and kinematics going on, there’s nothing too far out of the ordinary. The real trick here is combining a SCARA arm with a conveyor belt to give the project an infinite build volume. The proof of concept works, using a conveyor belt manufactured out of blue painter’s tape. These conveyor belt printers are new, and the bed technology isn’t quite there, but improvements are sure to come. Improvements will also be found in putting a small crown on the rollers to keep the belt centered.

All the files for this printer are available on the Gits, and there are already a few videos of this printer working. You can check those out here.

Earlier in March we heard about a quirk of the interconnected continental European electricity grid which caused clocks to lose about six minutes so far this year. This was due to a slight dip in the mains frequency. That dip didn’t put anything out of commission, but clocks that are designed to accumulate the total zero-crossings of the power grid frequency of 50 Hz don’t keep accurate time when that frequency is, say 49.985 Hz for an extended period of time.

An interesting set of conversations popped up from that topic. There were several claims that modern alarm clocks, and most devices connected to mains, no longer get their clock timing from mains frequency. I’ve looked into this a bit which I’ll go into below. But what we really want to know is: are your alarm clocks and other devices keeping time with the grid or with something else?

Simple clamps are great if you need to keep the pressure on two parallel surfaces, but if you have an irregular plane, or you need to cut through it, clamps are not the correct tool. The folks at [NYC CNC] feature a video with a clever hack borrowing from other disciplines. Painters tape is applied to the top of a level mounting surface in the machine and then burnished. The same is done to the bottom of the workpiece. Superglue is drizzled between the tape layers and pressed together so now the stock is held firmly below the toolhead.

Some parts are machined in the video, which can be seen below, and the adhesion holds without any trouble. One of the examples they cut would be difficult to hold without damage or stopping the machine. The accepted wisdom is that superglue holds well to a slightly porous surface like tape, but it doesn’t like do as well with smooth surfaces like metal. Removing residue-free tape at the end of a cut is also cleaner and faster than glue any day.